1. Field of Invention
This invention concerns an improved sight system for archery based upon micro-sized, parallax-free sights and the optimum deployment and mounting of such rights.
2. Prior Art
Bead sights are widely employed in archery and their application has been substantially enhanced by the availability of mounting brackets that enable a plurality of bead sights to be disposed one above the other in semi-fixed multi-range sighting systems. Usually the position of each bead sight is preselectably adjustable in both the lateral and vertical directions. A variety of techniques are employed to provide for adjustment, with bead-carrying threaded rods clamped by finger nuts in one or more vertically extending slots in the mounting bracket being common.
The greatest limitation of such sights is that they are subject to parallax errors. Any drift in anchor point or head orientation results in the rearward end of the arrow being inadvertantly offset and the arrow not flying as aimed, even though the shooter percieves his aim to be true.
The telescopic sight represents a known means for implementing a parallax-free fiducial reference of aim. Bow mounts for single telescopic sights are disclosed in U.S. Pat. No. 3,266,149 by L. Y. Powell, in U.S. Pat. No. 3,302,292 by Aikin and in U.S. Pat. No. 4,291,469 by N. J. Weast. None of these offers the large range span, compact size, ability to accomodate bows of different velocities, cost effectiveness and indication of accuracy reducing bow hand torque as does the sight system of my invention.
A group of parallax-free sights working on a common principle, herein as a class termed restricted-field direct-view collimator sights, have been disclosed by G. C. Luebkeman et al. in U.S. Pat. No. 3,362,074, by W. E. Steck III in U.S. Pat. No. 3,700,339, by G. C. Luebkeman in U.S. Pat. No. 3,912,400 and by C. J. Ross in U.S. Pat. No. 3,949,482. While disclosed for many years, the restricted-field direct-view collimator sight has yet to find acceptance in archery. Briefly this sight can be thought of as only the occular portion of a telescopic sight, in which the fiducial reference is formed. The objective and inverting portions of the telescope are deleted and the lateral dimensions of the resulting sight are restricted so that the target can be viewed around rather than through the sight. Being parallax- free, this type of sight is of potential value in archery where range is limited by the weapon and magnification is more often a detriment than an asset, especially in hunting which is the primary force supporting commercial archery. My invention is based upon the belief that the factors preventing commercial acceptance of this type sight in archery are the lack of the proper sight system concept as well as lack of associated means for mounting such sights to the bow with the necessary adjustability, convenience, and ruggedness. The thrust of my invention is to provide such a system concept and such mounting means.
It is also known art to affix independantly adjustable front and rear sights to an archery bow on a cross member of extended length, see for example BOW AND ARROW, Febuary 1984, pg. 8. While directional in character, as are the refractive sights discussed above, the front-rear sight arrangement requires alignment of two references to the target rather than one, which is a much greater burden when aiming a bow held at full draw than when aiming a lightly triggered fire-arm. In addition such sights are bulky if provided with adaquate base length and interpolation between sights on intermediate range targets is far more difficult than for the sight system of my invention.